1. Field of the Invention
The present invention relates to a plasma display device, and more particularly, to a plasma display device including a plasma display panel and an energy recovery circuit.
2. Description of the Related Art
A plasma display panel (PDP) of a plasma display device emits light from phosphors excited by ultraviolet (UV) rays generated during the discharge of an inert gas mixture to display an image. The plasma display device can be made thin and large and provides remarkably improved picture quality due to recently enhanced technologies. In particular, wall charges are accumulated on the surface of a three-electrode AC surface discharge plasma display device to protect the electrodes against sputtering generated by the discharge. Therefore, the three-electrode AC surface discharge plasma display device can be driven at a low voltage and has a long life.
Recently, a plasma display device with improved brightness and responsiveness has become available. A high voltage of about 200V is to be alternately applied from the sustain circuit of the plasma display device to the scan electrodes, the sustain electrodes, or the address electrodes of the plasma display device. Since capacitance exists between the electrodes, significant energy is lost to charge and discharge the capacitance. In order to solve the problem, an energy recovery circuit that includes an auxiliary inductor and an energy storage external capacitor is included in the plasma display device to reduce the amount of energy lost.
FIG. 1 is a schematic circuit diagram illustrating an energy recovery circuit included in a typical plasma display device.
Referring to FIG. 1, the energy recovery circuit generally includes a first switch SW1′ to a fourth switch SW4′, a voltage recovery capacitor Ca, and an inductor L.
The first switch SW1′ is coupled between a panel capacitor Cp and the voltage recovery capacitor Ca to selectively transmit a 1/2 address voltage Va/2 to the panel capacitor Cp.
The second switch SW2′ is coupled between the panel capacitor Cp and the voltage recovery capacitor Ca to selectively recover a voltage (e.g., a predetermined voltage) from the panel capacitor Cp to the voltage recovery capacitor Ca. The third switch SW3′ is coupled between an address voltage Va source and the panel capacitor Cp to selectively transmit the address voltage Va to the panel capacitor Cp.
The fourth switch SW4′ is coupled between the panel capacitor Cp and a base voltage GND to selectively apply the base voltage GND to the panel capacitor Cp.
The voltage recovery capacitor Ca is coupled between a connection point between the first switch SW1′ and the second switch SW2′ and the base voltage GND. The voltage recovery capacitor Ca transmits a voltage (e.g., a predetermined voltage) to the panel capacitor Cp through the first switch SW1′ or recovers a voltage (e.g., a predetermined voltage) from the panel capacitor Cp through the second switch SW2′. Here, the 1/2 address voltage Va/2 is charged in the voltage recovery capacitor Ca.
The inductor L is coupled between another connection point between the first switch SW1′ and the second switch SW2′ and the panel capacitor Cp. The inductor L forms a resonance circuit together with the panel capacitor Cp.
The operation of the energy recovery circuit having the above described structure will be described as follows.
First, when the first switch SW1′ is turned on, the potential of the address electrode A increases to the address voltage Va due to the resonance of the panel capacitor Cp and the inductor L.
Then, when the third switch SW3′ is turned on, the potential of the address electrode A is sustained as the address voltage Va. When the second switch SW2′ is turned on, the potential of the address electrode A is reduced to the level of the base voltage GND due to the resonance of the panel capacitor Cp and the inductor L. Then, the fourth switch SW4′ is turned on, and the potential of the address electrode A is sustained as the level of the base voltage GND.
In the energy recovery circuit included in the above-described plasma display device, when a power source is supplied to initialize the plasma display device, charge corresponding to the 1/2 address voltage Va/2 is not charged in the voltage recovery capacitor Ca. In addition, in the pixels that are not selected in a previous step, the 1/2 address voltage Va/2 is not charged in the voltage recovery capacitor Ca.
When the first switch SW1′ is turned on in a state where the 1/2 address voltage Va/2 is not charged in the voltage recovery capacitor Ca, the potential of the address electrode A increases to a potential lower than the address voltage Va.
Then, when the third switch SW3′ is turned on, the address voltage Va is applied to the address electrodes A. Here, since a difference between the applied address voltage Va and the voltage at the address electrodes A is large, the amount of inrush current rapidly increases. Therefore, the maximum value of the voltage applied to the address electrodes A increases rapidly as well. Here, the abnormal maximal voltage may be larger than the withstand voltages of the switches SW1′-4′ or the diodes that constitute the energy recovery circuit, therefore the switches SW1′-4′ or the diodes may not operate normally.
In order to solve the above-described problem, a structure in which the voltage recovery capacitor is charged faster during the initial driving of the plasma display device so that the voltage peak of the electrodes is removed and that the plasma display device is stably driven is disclosed in Korean Publication No. 20060086768.
However, in a method of precharging the voltage recovery capacitor during the initial driving of the plasma display device using resistance distribution as illustrated in the Korean Publication No. 20060086768, charging time is long so that a circuit operation is slow. In addition, although the resistance of the energy recovery circuit can be reduced in order to reduce the charging time, power consumption is increased. That is, in the energy recovery circuit published in the Korean Publication No. 20060086768, the power consumption and the heat dissipation increase as the charging time becomes shorter.